Milking sampling for diagnostic purposes

ABSTRACT

Methods and apparatus enabling a diagnostic test to be carried out on milk flowing in a milk line from an animal being milked, without interrupting the milking process, in which a portion of the milk is diverted through a by-pass in which an extracting means (14) in the form of a vacuum-operable pump and timer acts to separate from the milk flowing in the by-pass a milk sample and to deliver said sample through an associated sampling valve (16) to a testing device (18).

This application is a division of U.S. patent application Ser. No.104,789, filed Aug. 10, 1993, now U.S. Pat. No. 5,388,549.

FIELD OF THE INVENTION

This invention relates generally to milk sampling for diagnosticpurposes, and more specifically to a method and apparatus for extractinga sample of milk to be tested from the milk line in a milking system,whilst substantially avoiding interruption of the routine milkingprocedure.

BACKGROUND OF THE INVENTION

Milking of an animal is effected by means of a claw having attachedthereto cups which are connected to the animals teats. In the mechanisedsituation which exists in a milking installation, a milk line connectsto the claw to receive the milk. In order to draw off the milk, aconstant vacuum of about 0.5 Bar is applied to the milk line, switchableon and off by a valve. The vacuum is switched on prior to commencementof milking and connects the cups to the teats. After milking has beencompleted, the vacuum is switched off. A second vacuum system provides apulsating vacuum to the outside of the liners, to stimulate milk flowand maintain blood circulation in the teats. It will be understood,therefore, that in the environment of a milking installation, there aregenerally available two sources of vacuum namely a constant or steadyvacuum and a pulsating vacuum.

THE INVENTION

According to one aspect of the present invention, there is provided amethod of extracting a sample of milk from a milk line to which a vacuumis applied, for extracting milk from an animal, according to which aportion of the milk is a milk/air mixture flowing in the milk line isdiverted through a by-pass, in which is provided an extraction meansoperable by at least one of a fixed vacuum and a pulsating vacuum forseparating from the milk flowing in the by-pass a sample thereof anddelivering it to a testing device.

The said extraction means may also serve to control activation of thetesting device for the purpose of testing the extracted milk sample.

Initiation of an operating cycle to the sample extracting means may beeffected manually.

Preferably, in an upstream part of the sample extracting means, the milkflowing in the by-pass is raised to a pressure slightly above atmospherepressure. This is desirable in order to cause the sample of milk to bedelivered to the testing device, notwithstanding the vacuum which isappplied to said by-pass to cause milk to be drawn through the milk linewhen said means is not delivering a sample.

Preferably, the operating cycle of the sample extracting means is timed,and milk is delivered to the testing device only for a portion of saidoperating cycle. Thus, according to another aspect of the invention,there is provided a method of extracting a sample of milk from a milkline to which a vaccuum is applied for extracting milk from an animal,according to which a portion of the milk flowing in the milk line isdiverted through a by-pass, in which is provided an extraction meansoperable by at least one of a fixed vacuum and a pulsating vacuum forseparating a sample from the milk flowing in the by-pass and deliveringthe sample to a testing device, the extraction means being operable overan operating cycle which is timed. When the sample extracting means alsocontrols activation of the testing device, the latter may be activatedfor a subsequent portion of the operating cycle.

Preferably, at the junction where the by-pass connects to the milk line,the line is so formed as to produce a reservoir of milk. In this way aconstant flow of milk is generated through the by-pass.

In a preferred method, at a delivery device from which milk is deliveredto the testing device, when the delivery device is restored to open theby-pass to a through flow of milk, a temporary inflow of air through thedelivery device caused by the vacuum applied in the by-pass, cleans thedelivery device of residual milk.

Preferably, when the milk line is cleaned by flushing with cleaningfluid following the completion of a milking operation, the cleaningfluid also passes through the by-pass to clean the sample extractingmeans and delivery device.

The invention also relates to sample extracting apparatus for carryingout the above described method.

According to another aspect of the invention there is provided apparatusfor extracting a sample of milk from a milk line to which a vacuum isconnectable, the milk line in use being connected to an animal beingmilked, comprising a sample extracting means for passing a flow of milkreceived from the milk line, said means comprising a pump forpressurizing milk and for operating a timer, and a sampling valvereceiving the pressurized milk and for delivering a sample of milk to adiagnostic testing device, said sampling valve being operable undercontrol of the timer.

Preferably the milk pump and the sample valve are vacuum operated.

Where a pulsating vacuum is available, the milk pump may to advantage beoperated by the pulsating vacuum, whilst the sampling valve ispreferably operated from a source of steady vacuum.

The testing device may also be an actuable device for carrying out thediagnostic test, and this device also may be operable by a steady vacuumunder control of the timer.

If desired a plurality of testing devices for carrying out differentdiagnostic tests may be similarly operated and controlled.

One such diagnostic test may be a test for progesterone content of themilk.

A preferred pump is single acting reciprocating pump. The linear strokeof the pump piston is preferably converted to a rotary movement by asuitable transmission device, for example a double-ratchet mechanismwhich indexes a gear wheel on both the forward and reverse strokes ofthe pump.

In a preferred embodiment, the timer is driven by the transmissiondevice through reduction gearing. In the timer, one or more timing camsare driven through a clutch, such as a wrap spring clutch, whichincludes a manually operable release, eg. a pawl. When the pawl isreleased, as by a push-button, an operating cycle is initiated duringwhich the timing cam or cams are permitted to perform one completerevolution. A camming surface on one of the timing cams mechanicallycontrols a valve which opens a steady vacuum to the sampling valve for aportion of the operating cycle, thereby diverting the pressurized flowof milk through the sampling device to the testing device. During alater portion of the operating cycle, a camming surface on anothertiming cam may in similar manner cause activation of the testing device.Except when the sampling valve is operated, milk flows through the pumpand the sampling valve. Thus, when the milk line is flushed following amilking operation, cleaning fluid also flows through the sampling means.

In a preferred sampling system, the sampling means is connected as aby-pass to a primary milk line. Preferably, at the junction where theby-pass joins such milk line, a collector is provided in the milk lineto collect and retain a reservoir of the flowing milk. In this way, milkflows continously through the by-pass, even though the primary milk lineis erratically passing a flow of milk, froth and air.

DESCRIPTION OF EMBODIMENTS

The method and apparatus in accordance with the invention areexemplified in the following description, making reference to theaccompanying drawings, in which:

FIG. 1 is a block diagram of a sampling system;

FIGS. 2 and 3 show a sampling pump and timer unit respectively in twoside views;

FIG. 4 shows a detail of the pump and timer unit;

FIGS. 5 and 6 show a sampler valve, respectively in non-operated andoperated conditions; and

FIGS. 7 and 8 show an actuable testing device, respectively in elevatedand plan views.

FIG. 9 illustrates the milk collector of FIG. 1.

Referring to FIG. 1, the sampling system is connected to a milk line 10to which a vacuum is applied during milking and through which, in use,is flowing milk being collected from an animal being milked. In fact, inuse the line 10 is passing a mixture of milk, froth and air.

The sampling system is in the form of a by-pass connecting to the milkline at a collector 12, which is simply a portion fitted into the milkline having a depressed base, so as to form a reservoir for milk. Byvirtue of the collector 12, milk flows through the sampling system inthe form of a continous stream.

In addition to the collector 12, the sampling system includes a pump andtimer unit 14 and a sampling valve 16. An actuable testing device 18 mayalso be regarded a part of the system. In FIG. 1, the solid black lineindicates milk flow, the dotted line indicates an applied fixed vacuum,and the dash-dotted line indicates an applied pulsating vacuum.

A pulsating vacuum is applied to operate the pump and timer unit. Thetimer controls the application of a steady vacuum for operating thesampling valve and the testing device.

The pump and timer unit 14 as depicted in FIG. 3 comprises a pump on theleft-hand side and a timer on the right-hand side. The pump comprises anupper chamber 20 in the upper part of which reciprocates adiaphragm-supported piston 22 under the action of a pulsating vacuumapplied at the inlet port 2 4 and of a return spring 26.

The pump also has a lower chamber 28 in which reciprocates adiaphragm-supported secondary piston 30. The lower chamber has a milkinlet 32 and a milk outlet 34, each associated with a one-way valve 36,whereby milk entering the pump, under the influence of the vacuumapplied to the milk line, is raised in pressure to slightly aboveatmospheric pressure. The pressurized milk then passes to the samplingvalve 16.

As shown in FIG. 4, the piston 22 in the upper chamber 20 drives adouble ratchet mechanism in the form of gear wheel 38 and oppositelyacting pawls 40, whereby the linear motion of the piston is convertedinto a stepped rotary movement of the gear wheel. The gear wheel 38drives the timer. Thus, reverting to FIGS. 2 and 3, the gear wheel 38couples, through reduction gearing 42, 44 with a disc 46 forming part ofa wrap spring clutch 48 carried by a shaft on which are also mounted twotiming cams 50, 52. The camming surface 54 on one of these cams isvisible in FIG. 2.

The wrap spring clutch also includes a pawl 56 normally engaging with astep in the periphery of the disc 46, therby to prevent rotation of saiddisc, whereby the timing cams are also held against rotation. However,the pawl 56 can be lifted by, for example, a manually depressedpush-button 58, thereby causing the clutch spring to tighten and, startan operating cycle of the timer in which one complete revolution of theshaft carrying the disc and the timing cams takes place. In practice,such an operating cycle occupies about 300 strokes of the pump, takingabout 5 minutes.

The timing cams mechanically control two valves, one of which is shownin FIG. 2, one controlling application of the steady vacuum to thesampling valve 16 and one controlling application of the steady vacuumto the testing device 18.

The sampling valve is shown in FIGS. 5 and 6, and comprises a valvemember 60 having a head 62 in a milk chamber 61 which passes milkreceived from the pump, the milk entering at port 65 and leaving at port67. The valve member 60 is operable by movement of a diaphragm actingthereon via member 63. Thus, when the timing cam 50 causes the steadyvacuum to be applied at the inlet port 64, the valve member 60 is liftedfor a short period during which a sample of milk is delivered fromoutlet 66, from the milk chamber, to the testing device. When the steadyvacuum is withdrawn from the inlet port 64, spring 68 returns the valvemember to the closed position.

It is to be noted that, except when the valve member is operated, thereis a through-flow of milk through the milk chamber back to the milk lineso that the milk delivered to the testing device is representative ofthe milk flowing through the milk line at that instant. It also followsthat, when the system is flushed with cleaning fluid after completion ofa milking Operation, the sample valve is also washed clean. Moreover,when the valve member is restricted to close the milk sample outlet, amomentary back surge of air occurs through said outlet, due to theapplied vacuum in the milk line, which sucks any milk clinging to themating surfaces of the valve member and valve seat back into the milkchamber.

The diagnostic testing device per se forms no part of the presentinvention. As illustrated in FIGS. 7 and 8, however, it comprises upperand lower relatively rotatable cups, respectively 70 and 72, withopenings in the base of the upper cup which can be aligned with orclosed off from reagent chambers in the lower cup. The milk sample isretained in the upper cup until the cups are relatively rotated torelease some of the milk sample into the reagent chambers.

Relevant to the present invention is the actuator means for effectingthe necessary relative rotation of the cups. This occurs after the milksample has been delivered to the upper cup from the sampling valve,which is ensured by appropriate positioning of the camming surface onthe timing cam 52 relative to that of the camming surface in the timingcam 50 which controls the sampler valve.

As shown in FIG. 8, in particular, the actuator means comprises aratchet 74 on a cylindrical member 76 which is sealingly slideablerelative to a fixed cylindrical member 78 under the influence of thesteady vacuum, when applied at inlet port 80. Ratchet 74 drives a gear82 carried by the rotatable cup. Restoration of the member 76 is bymeans of an internal spring 84.

It will be appreciated that, by providing more timing cams on the timerof FIGS. 2 and 3, it is possible to actuate more than one actuabletesting device, for carrying out different diagnostic tests, or toactuate a testing device requiring more than one actuation.

Various modification of the above-described and illustrated arrangementare possible within the scope of the invention hereinbefore defined. Inparticular, for carrying out the method generally illustrated in FIG. 1,various other constructions of pump, timer and sampling valve, operableby steady and/or pulsating vacuum, may be employed.

FIG. 9 illustrates the milk collector 12 of FIG. 1. Milk 13 collects inthe depression 15 and is drawn off along tube 17 to the pump and timerunit 14.

I claim:
 1. A method of extracting a sample of milk from a milk line towhich a vacuum is applied for extracting milk from an animal, comprisingthe steps of:diverting a portion of milk in a milk/air mixture flowingin a milk line through a by-pass, providing in the by-pass a vacuumoperated milk sample extraction means, operating the milk sampleextraction means by at least one of a fixed vacuum and a pulsatingvacuum, whereby to separate a sample of milk from the milk flowing inthe by-pass, and operating the milk sample extraction means over a timedoperating cycle.
 2. A method according to claim 1, in which the saidextraction means also serves to control activation of the testing devicefor the purpose of testing the extracted milk sample.
 3. A methodaccording to any of claim 1, in which, in an upstream part of the sampleextracting means, the milk flowing in the by-pass is raised to apressure slightly above atmosphere pressure.
 4. A method accoding toclaim 1, in which an operating cycle of the sample extracting means istimed, and milk is delivered to the testing device only for a portion ofsaid operating cycle.
 5. A method according to claim 4, in which thesample extracting means controls activation of the testing device for asubsequent portion of the operating cycle.
 6. A method according to anyof claim 1, in which, at a junction where milk is diverted into theby-pass, the milk line is so formed as to produce a reservoir of milkfrom the milk/air mixture flowing in the milk line.
 7. A methodaccording to claim 6, in which a milk collector is provided at the saidjunction in the form of a portion of the milk line having a depressedhose.
 8. A method according to claim 1, in which, at a delivery devicefrom which milk is delivered to the testing device, when the deliverydevice is restored to open the by-pass to a through flow of milk, atemporary inflow of air through the delivery device, caused by thevacuum, applied in the by-pass, cleans the delivery device of residualmilk.
 9. A method according to claim 8, in which, the milk line iscleaned by flushing with cleaning fluid following the completion of amilking operation, the cleaning fluid also passes through the by-pass toclean the sample extracting means and delivery device.
 10. A method ofextraction a sample of milk from a milk line to which a vacuum isapplied for extracting milk from an animal, comprising the stepsof:diverting a portion of milk in a milk/air mixture flowing in a milkline through a by-pass, providing in the by-pass a vacuum operable milksample extraction means, operating the milk sample extraction means byat least one of a fixed vacuum and a pulsating vacuum, whereby toseparate sample of milk from the milk flowing in the by-pass, deliveringthe milk sample to a diagnostic testing device, and operating the milksample extraction means over a timed operating cycle.
 11. A methodaccording to claim 10, in which initiation of an operating cycle of thesample extracting means is effected manually.
 12. A method according toclaim 10, in which the milk is delivered to the testing device only fora portion of the operating cycle.
 13. A method according to claim 10, inwhich the said extraction means also serves to control activation of thetesting device for the purpose of testing the extracted milk sample. 14.A method according to claim 10, in which, in an upstream part of thesample extracting means, the milk flowing in the by-pass is raised to apressure slightly above atmosphere pressure.
 15. A method according toclaim 10, in which an operating cycle of the sample extracting means istimed, and milk is delivered to the testing device only for a portion ofsaid operating cycle.
 16. A method according to claim 15, in which thesample extracting means controls activation of the testing device for asubsequent portion of the operating cycle.
 17. A method according toclaim 10, in which, at a junction where milk is diverted into theby-pass, the milk line is so formed as to produce a reservoir of milkfrom the milk/air mixture flowing in the milk line.
 18. A methodaccording to claim 17, in which a milk collector is provided at the saidjunction in the form of a portion of the milk line having a depressedhose.
 19. A method according to claim 10, in which, at a delivery devicefrom which milk is delivered to the testing device, when the deliverydevice is restored to open the by-pass to a through flow of milk, atemporary inflow of air through the delivery device, caused by thevacuum, applied in the by-pass, cleans the delivery device of residualmilk.
 20. A method according to claim 19, in which, the milk line iscleaned by flushing with cleaning fluid following the completion of amilking operation, the cleaning fluid also passes through the by-pass toclean the sample extracting means and delivery device.